A combustion gas (exhaust gas) discharged from an automotive engine is discharged to the outside through an exhaust manifold, a catalytic converter provided directly below the exhaust manifold, a front tube, an underfloor catalytic converter, a center muffler, a main muffler, and the like (see Patent Document 1 (JP-A-11-81976, for example).
An automotive engine is designed so that the amount of fuel is increased in a high-load/high-revolution region. In this case, a high-temperature exhaust gas flows through the main muffler and the like, and a large amount of heat is released toward the main body of the vehicle positioned opposite to the main muffler and the like. This accelerates thermal deterioration in a resin member or a rubber member (e.g., bumper) that forms the main body, grease applied to a member that forms the main body, or the like.
Therefore, an automotive exhaust pipe (automotive exhaust gas discharge pipe) has been desired that can suppress thermal deterioration in the main body of a vehicle when the automotive engine is operated at high speed.